Oliensis negative asphalt production



United States Patent OLIENSIS NEGATIVE ASPHALT PRODUCTION George M. Longland, Jr., Harrisburg, Pa.,' assignor to Tfhe Pure Oil Company, Chicago, 111., a corporation 0 Ohio No Drawing. Application December 16, 1955 Serial No. 553,420

4 Claims. (Cl. 208-41) This invention relates to a method of preparing asphalts. More particularly, this invention is directed to a method for preparing Oliensis-negative asphalts.

The term asphalt is applied to a species of bitumen, also to certain pyrogenous substances of dark color and variable hardness, which are comparatively non-volatile, composed principally of hydrocarbons, and contain little or no crystallizable paratfins. The definition covers native asphalts, that is, asphalts occurring naturally in a pure or relatively pure state or associated with certain mineral matter; pyrogenous asphalts obtained from the distillation, blowing, etc. of petroleums and classed as blown asphalts, residual oil, and residual asphalts; sludge asphalts; and asphalts precipitated from oils by means of liquefied hydrocarbon solvents such as propane.

Asphalt has found extensiveuse in paving materials for roads and sidewalks, as a roofing material, and as a floor covering. It has also been used for waterproofing various papers and other materials, in coating compounds, and in adhesives.

Certain asphalts derived from petroleum have been found to be superior to'others, particularly with respect to cohesion and wearing properties. A test has been dew'sed for characterizing certain of such superior asphalts and has been termed the Oliensis asphalt spot test. Most asphalts giving a negative Oliensis test are superior to those giving a positive Oliensis test. This test is fully described in the American Association of State Highway Officials bulletin entitled FHighway Materials, p. 113 et seq., 1942 (see also same bulletin pp. 144146, 1947), and is briefly summarized hereinafter. The test is not applicable to natural asphalts containing non-bituminous matter insoluble in xylene. Difiiculty has arisen from a commercial utilization standpoint in that the supply of Oliensis-negative asphalts is limited, all too few asphalts produced being able to pass the test (show negative). The commercial value of Oliensis-positive asphalts has suffered due to their more limited scope of uses, and manufacturers of asphalts frequently have not been able to realize expected profits due to failure of their asphalts to meet the Oliensis asphalt spot testrequirements.

I have now discovered a method of preparing Oliensisnegative asphalts from crude oils which normally yield Oliensis-positive asphalts. Moreover, I have discovered a method of determining Whether ornot the asphalt to be prepared from a crude oil residue will, when prepared, pass the Oliensis asphalt spot test.

Accordingly, it is an object of my invention to prepare Oliensis-negative asphalts.

It is another object of my invention to prepare Oliensisnegative asphalts utilizing mixtures of crude petroleum o-il residues normally yielding Oliensis-negative asphalts and those yielding Oliensis-positive asphalts.

It is also an object of my invention to prepare Oliensisnegative asphalt compositions containing Oliensis-positive asphalts. I A

It is a further object of my invention to provide a method of determining whether or not a petroleum residue will yield on conventional treating an Oliensis-negative asphalt.

In general, my invention comprises determining the characterization factor of an asphaltic petroleum residue and relating it to the Oliensis asphalt spot test in such manner as to make possible the preparation of Oliensisnegative asphalt.

More particularly, my invention relates to the discovery of an unexpected relationship between the characterization factor of an asphaltic petroleum residue and the ability or inability of an asphalt prepared therefrom to pass the Oliensis asphalt spot test. My invention also includes the blending of Oliensis-negative asphalt compositions with Oliensis-positive asphalts to make Oliensisnegative asphalt.

A particular point of novelty of my invention lies in the discovery that asphaltic petroleum oils, when reduced to 580 F. flash point bottoms or residues which exhibit characterization factors of up to about 12, yield Oliensisnegative asphalts.

The Oliensis asphalt spot test may be briefly summarized as follows:

An asphalt sample weighing 2:0.02 g. is placed in a 50 ml. glass flask (Florence or wide-mouth, flat bottom) so that it covers the bottom and lower portion of the flask. Into the flask is then placed 10.2 ml. of a standard naphtha (solvent) from straight-run, overhead petroleum distillates, free of cracked products and of the following characteristics:

Gravity, A.P.I. 49-50 Distillation:

Initial boiling point Above 300 F. (149 C). 50% Over 335-355 F. (168-179" C.) End point Below 410 F. (210 C.)

Aniline point 138145 F. (5963 C.)

Such a suitable solvent is naphtha commercially known as Skelly Solve S, obtainable from the Skelly Oil Co., Kansas City, Missouri.

Into the flask is quickly placed a cork stopper fitted with an' 8 in. length of A glass tubing, and the flask is swirled for 5 sec., then immersed in gently boiling water from which it is removed and swirled for 5 secs. at 1 min. intervals until complete dispersion has taken place. If

complete dispersion is not obtained within 8 minutes, the

procedure is repeated with new samples but at 25 F. higher temperature increments until complete dispersion within 8 mins. can be obtained.

After complete dispersion, the glass tube is lowered below the solution level and the flask cooled for 30 min. at room temperature.

It is then warmed for 15 min. at 3210.5 C.,'thoroughly stirred, and a drop of the mixture is placed on Whatman #5 filter paper. After 5 min, the spot is examined by holding the paper at arms length with the plane of the paper at about right angles to. the line of vision with a good light source at the observers back. If the drop forms a brown or yellowish-brown circular stain, With a darker solid or annular nucleus in the center, the test is positive. If the drop forms. a uniformly brown circular stain, the asphalt-solvent mixture is. set aside in subdued light at roomtemperature, then retested by observing the coloration ofan additional. drop on the same type of filter paper underthe above-described conditions (warming to 3220.5 C., stirring). If the drop from the 24 hr. old mixture still forms a uniformly brown circular spot, the test is negative, but 'iffthe above-described darker solid or annular nucleus is found, .the test is positive.

Provision is also made for .retesting doubtful specimens and for determining the xylene equivalents of Oliensispositive asphalts.

The characterization factor of a petroleum oil fraction may be determined according to the following formula:

Characterization factor: 3

where:

T =50% molal boiling point, Rankine. The Rankine scale is 460 F.= R., that is, a scale based on absolute zero of the Fahrenheit scale, and comparable to the Kelvin scale for Centigrade measurement.

S=Specific gravity at 60 F.

Characterization factors have been approximately correlated with the parafflnicity of oils, their hydrogen contents, aniline points, thermal expansion properties, viscosity, and processing and cracking rates, but never before, to the knowledge of this inventor, with the ability or inability of an oil to yield an Oliensis-negative asphalt.

I have determined the characterization factors for a number of crude oil bottoms having a flash point of 580 F. and have directly related them to the results obtined on asphalts having a flash point of 630 F. prepared therefrom by conventional methods and tested by means of the Oliensis asphalt spot test above-described.

The petroleum oil fractions of 580 F. flash point, from which the 630 F. flash point asphalts were prepared, were obtained by conventional vacuum distillation, leaving a residue or bottoms having the 580 F. flash point. Other distillation techniques, such as steam distillation may be used but care must be exercised to avoid substantial cracking of hydrocarbon constituents of the oil. The invention is not applicable to asphalts prepared by techniques such as air blowing, etc. which modify the chemical structure of the oil.

The asphalts were prepared from these 580 F. flash point residues by the same general technique as for the preparation of 580 F. residue, that is, flash distillation under vacuum.

The following Table I sets forth the characterization factors of various petroleum residua and the Oliensis asphalt spot test results for their respective asphalts:

As seen in Table I above, the asphalt prepared from 5 80 F. flash point residues having a characterization factor below 12 was negative, both initially and after 24 hours. Asphalt prepared from residues having a characterization factor of 12.07 was positive, while asphalt from bottoms or residua of 12.04 characterization factor was initially negative, then borderline positive (doubtfully positive). The asphalt prepared from bottoms derived from a mixture of oils, some of which yielded Oliensisnegative asphalts, and others Oliensis-positive asphalts, where the composite 580 F. flash point bottoms had a characterization factor of 12.03, was initially negative and very slightly positive after 24 hours. Bottoms prepared from a similar blend of oils where the composite bottoms had a characterization factor of 12.21 produced a positive asphalt.

Where 580 F. flash point flash residue has a characterization factor of less than about 12.00, Oliensisnegative asphalts result, while borderline asphalts are produced where the bottoms characterization factor is in the range of about 12.00-12.05. Suitable examples of oils yielding 580 F. flash point bottoms with characterization factors under 12.00 are: Vinton (11.97), Bonanza (11.39), Common Stream (11.83), Kansas Sweet (11.75), and West Texas Sour (11.62). Oliensispositive asphalts are produced from bottoms having characterization factors of about 12.06 and above. Mixtures of crudes, the bottoms of which have characterization factors in the above-stated ranges, produce asphalts which perform with respect to the Oliensis spot test in the same manner as the bottoms from single crudes of the same ranges. Thus, for example, the asphalt from the mix having a 12.21 characterization factor was similar in the Oliensis spot test to asphalt from East Texas crude (12.07), while the asphalt from the mix having a characterization factor of 12.03 was similar to that from Intermediate Sweet West Texas crude (12.04) in the Oliensis spot test. Thus, blends of oils which yield bottoms having characterization factors above 12 with those yielding bottoms having characterization factors below 12 can be prepared by simple proportional mixing to produce bottoms having composite characterization factors below 12 and from which Oliensis-negative asphalts may be prepared.

Although the characterization factors given above were obtained on residua of 580 F. flash point, and Oliensis tests were made on 630 F. flash point asphalt, it is satisfactory, though less preferable, to determine characterization factors on heavier residues and Oliensis values on lighter residues, in which case different characterization factor criteria will apply, viz., the required factor may be greater or less than 12.00. Technical and mechanical difficulties are experienced in determining characterization factors on heavier residues and in performing the Oliensis test on lighter bottoms, which are minimized by using 580 F. and 630 F. flash point bottoms.

My method for preparing an Oliensis-negative asphalt from oil or residue normally producing Oliensis-positive asphalt comprises blending therewith crude oil or residues which have a 580 F. flash point residue with a characterization factor below 12, such that the composite characterization factor of the resulting blend is 12 or below for 5 F. bottoms, and then removing lighter fractions, if necessary, to obtain asphalt of desired flash point. An asphalt which tests negative initially and after 24 hrs. in the Oliensis asphalt spot test is uniformly obtained.

Any single crude or mixture of crudes which yields 5 80 F. flash point residua having characterization factors of 12.00 or below will yield Oliensis-negative asphalts.

Example I below sets forth one embodiment of the process of my invention:

Example I The following crude oils, some of which have 580 F.

A sample of the blend is then reduced to 580 F. flash point bottoms by vacuum distillation. The residue obtained thereby is found to have a characterization factor of 11.91. The blend is then vacuum distilled to asphalt bottoms of desired flash point, that is, 630 F. This residue is tested by the Oliensis asphalt spot test in the above-described manner and found to be negative both initially and after 24 hours.

Thus, my invention has made possible the upgrading of undesirable, Oliensis-positive asphalts by relating the Oliensis test to characterization factors and properly blending together oils or residues according to their characterization factors so that said oils and/ or residues which normally produce lower grade asphalts (Oliensis-positive) may be utilized in a mixture with Oliensis-negative oils or residues to produce Oliensis-negative asphalts. The source of O1iensis-negative asphalts has accordingly been expanded and a method set forth for the preparation of increased yields of Oliensis-negative asphalts.

Modifications of equipment and processing steps as are within the skill of one versed in the art are within the scope of this invention.

I claim and particularly point out as my invention:

1. The process for the preparation of Oliensis-negative asphalt from non-oxidized petroleum oils consisting in blending together petroleum oil which produces Oliensispositive asphalt with petroleum oil which produces Oliensis-negative asphalt in proportions to give a characterization factor not greater than 12 when the blend is reduced under substantially non-cracking conditions to a flash point of about 580 F. and then reducing said blend to an asphalt of desired flash point.

2. The process in accordance with claim 1 in which 6 the blend is reduced to about 630 F. flash point asphalt under substantially non-cracking conditions.

3. The process for the preparation of Oliensis-negative asphalt from non-oxidized petroleum oils consisting in blending together petroleum oil which produces Oliensisnegative asphalt with petroleum oil which produces Oliensis-positive asphalt, reducing the blend by substantially non-cracking distillation to a residuum having a flash point of about 580 F., determining the characterization factor of such residue, adjusting the proportions of said oils in said blend to give a characterization factor of not greater than 12 when the blend is reduced to a flash point of about 580 F. as above set forth, and then reducing the blend to asphalt of desired flash point.

4. The process in accordance with claim 3 in which the reduction of the blend to asphalt is carired to a flash point of 630 F. under vacuum and substantially non-cracking conditions.

References Cited in the file of this patent UNITED STATES PATENTS 2,658,026 MacLaren et a1. Nov. 3, 1953 2,687,989 Goodwin Aug. 31, 1954 FOREIGN PATENTS 506,577 Great Britain May 31, 1939 OTHER REFERENCES Watson et al.: Characterization of Petroleum Fractions, Ind. Eng. Chem, vol. 27 (1935), pp. 1460-1464. 

1. THE PROCESS FOR THE PREPARATION OF OLIENSIS-NEGATIVE ASPHALT FROM NON-OXIDIZED PETROLEUM OILS CONSISTING IN BLENDING TOGETHER PETROLEUM OIL WHICH PRODUCES OLIENSISPOSITIVE ASPHALT WITH PETROLEUM OIL WHICH PRODUCES OLIENSIS-NEGATIVE ASPHALT IN PROPORTIONS TO GIVE A CHARACTERIZATION FACTOR NOT GREATER THAN 12 WHEN THE BLEND IS REDUCED UNDER SUBSTANTIALLY NON-CRACKING CONDITIONS TO A FLASH POINT OF ABOUT 580*F. AND THEN REDUCING SAID BLEND TO AN ASPHALT OF DESIRED FLASH POINT. 